1. Field of the Invention
This invention relates generally to expandable braided sleeves and, more particularly, to expandable braided sleeves formed of monofilament plastic fibers. The invention provides an expandable braided sleeve that, when pressed inwardly at its ends, expands and retains its expanded form until it is subsequently pulled at its ends to return it to its unexpanded form.
2. Description of the Prior Art
Braided plastic sleeves formed of monofilament plastic fibers are widely used as an outer sheath for electrical wire bundles. Such sleeves, which are typically formed of polyester filaments, make use of the filaments' natural "memory," i.e., the tendency of the filaments to return to their original shape when a distorting force is no longer applied. Typically, when the ends of an expandable braided sleeve are pushed axially inwardly toward each other, the diameter of the sleeve expands. If the ends are released, the sleeve automatically springs back to its unexpanded, narrow diameter form. The sleeve is inserted onto a wire bundle, for example, by simultaneously pressing the sleeve ends inwardly toward each other while at the same time threading the expanded sleeve onto the wire bundle. Once in place, the sleeve ends are released and the sleeve contracts tightly around the bundle. A degree of dexterity and skill is required to install such an expandable braided sleeve.
Because of their braided nature, expandable braided sleeves have a tendency to unravel or fray at their ends. One solution to this problem has been to cut the braided sleeve with a heated blade, which has the effect of melting and partially fusing or welding the individual filaments together at their ends. Although this is effective in avoiding fraying, it does have the effect of keeping the sleeve from expanding at its ends unless the "welds" between the individual filaments are manually broken immediately prior to use. This is an "extra step" that takes time, reduces convenience and makes the expanded braided sleeve somewhat more difficult and time consuming to use.
Examples of various braided sleeves are found in U.S. Pat. No. 4,870,887, which issued to Tresslar, et al. on Oct. 3, 1992 and U.S. Pat. No. 4,754,685, which issued to Kite, et al. on Jul. 5, 1988.